Refrigeration system



Oct. 16, 1945. BUEHLER, JR 2,387,117

REFRIGERATION SYSTEM 4 Filed March 24, 1941 4 Sheets-Sheet l LeonBUEHLERJR.

- I L BUEHLER. JR ,387,?

REFRIGERATIORSYSTEM Filed March 24, 1941 4 sheets-sr ieep-z Oct. 16,1945.

L BUEHLER, JR

REFRIGERATION SYSTEM Filed March 24, 1941 4 Sheet$-Sheet 3 4 Sheei-Sheet4.

L. BUEHLER, JR

REFRIGERATION SYSTEM 7 Filed Mm 24, 1941 4 gvvuq/wtm LEON BUEHLER,JR,,

IIIIIIIIII-HIIIIIIIHI Patented Oct. ,16, 1945 REFRIGERATION SYSTEIHLeonBuehler, Jr., Waynesboro, Pa., assignor to Frick Company,Waynesboro, Pa.

Y Application March 24, 1941, Serial No. 385,015 14 Claims. (Cl. 230-30) This invention relates to refrigeration systems and particularly tocompressors for use in-such systems.

An object of the invention is to provide a compressor incorporatingimproved means functioning to unload the compressor in accordance withload requirements.

The unloading means as herein disclosed is preferably of that typeoperating through pressure generated in the lubricating system for thecompressor, and the head of the compressor cylinder is of the springmounted safety type andcarries as part of its assembly a suction valvealso functioning as an unloadervalve normally urged towards open orunloading position by spring pressure, the oil pressure of thelubricating system being applied through a controldevice operating inaccordance with load requirements to move the suction valve to aposition where it will operate in its normal capacity as a suctionvalve. Thus the action of the capacity control 7 is not directlydependent upon the operation of the compressor yet at the same time theunloading pressure is applied through the lubricating system for thecompressor. This construction provides a remarkably flexible unloadingsystem Figs. 5 and 6 are sections taken substantially on the lines 5-5and 8-6, Fig. 2.

Referring. to the drawings in detail, a refrigeration compressor isgenerally indicated at I0 and has a crankcase H which at one end isprovided with a partition wall l2, note Fig. 2, formed then returning tothe crankcase for recirculation.

for the compressor and at the same time prevents damage in the event aslug of liquid or other substantially non-compressible body isinterposed between the top of the piston and the cylinder head.

Another object of the invention therefore, is to provide a compressorfor refrigeration systems embodying unloading means of a flexible natureand a safety head for the compressor cylinder or cylinders carrying aspart of its assemblya com- Fig. 3 is an enlarged sectional view of'oneof the compressor cylinder heads particularly illustrating the springmounted safety construction of the latter;

Fig. 4 is a sectional plan view taken on the'line The crankshaft may bedriven from any suitable source of power connected to pulley 22,

note Fig. 1, which is mounted on the end of the crankshaft beyond endplate 23. said shaft at this point being provided with a seal assemblygenerally indicated at 24, for preventing theescape of refrigerant.

. The head of each cylinder l8 carries a spring mounting assembly, oneof which is shown in detail in Figs. 3 and 4. The cylinder l8 at itsupper extremity is formed with a counterbore 25 which forms a 'seat forcylinder .head .26 and valve case 21. the case 21 and is formed with a.series of radial webs 28'. The head 26, case 21 and cage'28 areconnected as a unit by center bolt 29 and pins or studs 30. An annularrecess 3| in the head 26 provides a seat for valve spring 32, over whichder I8 is delivering at full load capacity.

In effecting unloading of the cylinder I8, the suction valve 33 isdisplaced from its seat 34 by control means including abutment sleeve 36connected to capacity control lift piston or plunger 31 s idable in thelower extremity of counterbore 2i and normally under spring pressure bymeans of springs 38 mounted on pins 39, the latter at their lower endseach being connected to the plunger 31 and at their upper endsprojecting into ring member leslidable in the upper extremity of thesaid counterbore.

A cage member 28' is disposed on The suction inlet space or port isgenerally indicated at M and the main exhaust space or port at 42, theseports being separated, by the ring member 40 and sleeve 43 which at itsupper end is pressed into the member a and at its lower end engages aseat ll formed on the top of the valve case 21. Port communicates withport ll through port or space I.

An inlet port 45 for pressure fluid is formed in the wall-abovethecylinder and leads into annular space 48 which is sealed by gasket"held in position by annular member l8.

It will be seen that as long as the pressure in annular space It issufllciently low to permit the springs ll to overcome valve spring 32,suction valve 33 will be displaced from its-seat 34, thereby permittinggas to surge back and forth in the said space when the piston I! isreciprocated, but

when pressure is built up in the space 48 to a point where it overcomesthe spring 38, the sleeve 3' will be moved upwardly iree ofthe suctionvalve 38, permitting the latter to seat and functlon in its normalmanner.

. The cylinder head 26 and valve case 21 are formed with communicatingexhaust or "discharge ports I! and 48' which are spaced radially fromone another and are controlled by annular disc valves in and I0 normallyurged to seated position by springs 5i housed by the webs movement ofthe valves 50 and ill away from head spring I! to the cap ll.

In the position shown in Fig. 3, the suction V valve 38 is in unloadingposition, the pressure in the space or chamber 40 being insuiiicient tooilset the pressure of the springs 38. 'When pressure builds up in thisspace, the plunger or pision 31 isdriven upwardly,'compressin'g springsIt and moving the abutment sleeve 38 clear of the' suction valve 33,permitting the latter to'iseat,

aseaur Within the chamber defined by the plate n and'cap 62 is a screenassembly comprising a screen which is of a particular construction toobtain maximum screening or filtration emciency. This screen is doubledupon itself or corrugated as indicated at 64' and compressed betweenplates .65 attached to base plate 66 at 61.

Oil coming into the inlet chamber flows into the screen and diverges,going both ways and filling the outer chamber 68, from which it passesinto pressure chamber 69 through port or passage I0. 011 under pressurein the chamber 89 feeds through port II to the bore 2| in the crankshaftand connecting rod and crankshaft bearings and then back into the sumpor well of the crankcase, to be recirculated. It will be understood thatthe oil for lubrication is not only carried through the 'bore 2| of thecrankshaft IE, but is also carried to the various bearings of thecompressor by drillin'gs in the connecting rods and by otherconventional means, not shown in detail. It will 'be noted that bydoubling the screen 64 upon itself not only results in a large screeningarea within a restricted space but also stifiens and reinforces thescreen.-

The oil pump 51 is preferably driven from the crankshaft It by means ofeccentric 12 which turns stud shaft or pin 13 mounted in bearing yolk l4and having secured thereon spiral pinion l5 whichdrives gear 18 securedon the upper end i of impeller shaft ll, note particularly Fig. 6, thesaid shaft being mounted at its'upper end in bearing I8, note also Fig.2.

The wall above the pressure chamber as is tapped at a number of pointsto provide for mounting an oil pressure gauge I9 and to accommodatesuitable pipe connections for the unloadeach piston.

whereupon the compressor plstoncan operate normally to drawin'reirigerant vapor through intake ports ll, ll past the suction valve33 and through port it into the cylinder on the down stroke-or thepiston, the suction valve being seated on the up stroke of the pistonand the com-' pressed refrigerant being discharged through ports 4! andI. outwardly through exhaust or! discharge passage 2 and port 42'.Should a slu ing system. It is preferred to control the unloading orcapacity ofthe compressor in steps or stages, that is, where one-fourthto one-half capacity reduction is desired, one stage of the control maytake care of one-fourth of the reduction and another stage the otherfourth. Preferably each cylinder of the compressor is provided with aseparate control and unloader mechanism. Hence. in the present instancethere: are three connections to the pressure chamber 89, one forHowever, since the control in each instance is the same, the descriptionof one will sufllce for all.

' A tube or pipe line 80 is tapped into the pressure chamber 89 at thepoint 80, such tube being or relatively small flow passage or conduit.The conduit 80 connects into a T coupling ll which has the one end orconduit 82 connected thereto and dischargin into of liquid or othersubstantially incompressible on body be encountered by the upwardly.moving piston, it will cause the head 20 to unseat against theresistance or spring. l8. This yielding movement or the saiety-headwillallow 'a longer period of time toset rid of the liquid; via. of thestroke of the piston il. 7

Referring now to the unloader pressure syste .thisisbestsbown-inl 'lg.2. Anoilpump "is mounted in the chamber I" and .is provided with animpeller chamber ll having connected thereto the intake end of a tube orconduit II which o. the e.

discharges oil into a chamber .0 defined by plate I GI and cap 82. notealso Fig. 6. The cap 62 and plsite 663i are bolted to the crank case bystud b0 ts the port ll, note Fig. 3 in conjunction with Fig.'

2. The line It is of greater ilow capacity or greater diameter than theline so. Leading from the coupling 8! is a return conduit Ol, 88' havingacapacity control may be 0! the The valve 14 may be magneticallyoperated so that its opening and closing can be controlled irom athermostat, pressure switch or the like indicated at ti and influencedby suction gas pressure, teu'lperslturev or the material being cooled;or temperature corresponding with suetion temperature. in certaininstances actuation or; the unloadinsvalve may be manual. In otherregulated in accordance with load rets and isnot dependent upon anytimed relation of the operation of the compressorsize and defining arestrictor v valve ll therein and which" type shown in my Patent2,140,415.

tuation ot'the capacity control is- I rid of the liquid and at the sametime relieves the The machine operates as follows;

When the machine is idle, the pump 51 is also idle and the pressure inthe chamber 69 will be at the crankcase pressure or suction pressure.Therefore, there will be no pressure in -the annular space or chamber 45beneath the plunger or capacity control lift piston 37, and hence thesprings 38 will force the plunger downwardly, thereby causing thesuction valve control sleeve 36 to hold the suction valve 33 clear ofits seat 35 against. the pressure of valve spring 32. The compressorcylinder will, therefore, start unloaded, thereby reducing the startingtorque.

When the valve 8t is, open, very little excess pressure can build up inthe pressure space or .chamber 46 even though the compressor is running,due to the fact that the line 80 acts as a restrictor and allows only asmall amount of liquid to pass, and the line 838 3' being of ample sizepermits practically all the liquidor oil that may pass through therestrictor line 80 to drain back into the crankcase. Therefore, when thevalve 80 is open, the springs 38 will bear downwardly on the plunger 31and sleeve 36 and overcome the opposed pressure of the valve spring 32so that the suction valve 33 will be held ofi its seat and will notfunction as a suction valve. How-.

ever, when the valve 84 is closed, liquid or oil passes through therestrictor line 80 and line 82 into the pressure chamber 46, allowingthe suction valve to close, whereupon the cylinder l8 will functionnormally to compress and pump as.

While the unloading system herein disclosed is particularly adapted forcontrol by steps or stages by means of an independent valve 84 andc'oacting connections for each cylinder, it will be understood that oneor a group of cylinders could be provided with a graduated control overany desired range by utilizing a control valve which would graduallyclose to thereby vary the pressure in chamber 46 to partially orcompletely unload the compressor cylinder or cylinders in accordancewith adjustment of the valve.

The operation of the valve 84 may be controlled by a pressure swimhactuated by suction pressure to the compressor so as to Open the valveand reduce the capacity when the pressure drops and to close the valveand increase the capacity when the suction pressure increases, or athermostat actuated by liquid refrigerant temperature, air temperature,chilled water temperature, etc.,

could be employed so as to reduce the capacity on falling temperatureand increase the capacity on rising temperature. Also, instead of anelectric valve, a direct pressure actuated valve con-.

nected to the suctionline could be employed, or even a directtemperature actuated valve controlled by the expansion and contractionof the fil":i in a thermostatic bulb.

It will thus be seen that the present unloader system readily lendsitself to a variew of capacity controls, either automatic or manual," soas to regulate the unloading action in accordance with loadrequirements.

The entire safety head assembly including the suction valve 33 is freeto slide vertically in the counterbore 25, but is normally held inseated position by spring 53. Should a slug of liquid enter thecylinder, the piston on its compression stroke will lift the safety headagainst pressure of the spring 53. At this-time, the discharge valves50, 50 will beopen and some of the liquid may escape through thesevalves. The yielding safety head allows a longer P riod of time to. get

' from the spirit and scope of the invention as-destrain from thecylinder head connections.

It will be understood that certain limited changes in construction anddesign of the various parts of the compressor and unloadingsystem asherein disclosed may be made without departing fined by the appendedclaims.

What is claimed is:

1. In a refrigeration system having a closed refrigerant circuit, acompressor having a cylinder with a piston therein and a crankcaseprovided with a force feed lubricating system, said cylinder beingprovided with spring-pressed suction and discharge valves, a controlmember adapted to en.- gage the suction valve and having coacting springreturn means of greater strength than the suction valve spring andwhereby the suction valve is displaced from its seat to unload thecylinder, means operatively connected with the lubricating system of thecompressors for applying fluid pressure to said control member toovercome the tension of its return springand move the member clear ofthe suction valve and permit unrestricted normal operation of thelatter, and means operating in accordance with load requirements of therefrigeration system for controlling the admission of fluid pressurefrom the lubricatingsystem to said control member.

2. 'In a refrigeration system having a closed refrigerant circuit, acompressor having a cylinder with a reciprocating piston therein and acrank case provided with a force feed lubrication system, a head forsaid cylinder provided with suction and discharge ports, suction anddischarge valves controlling saidports and valve springs tending tonormally urge said valves to seated position, a reciprocating controlmember adapted to engage the suction valve and having coacting springmeans of greater strength than the suction valve spring and whereby thelatter valve is nor-' mally urged from its seat to unload the cylinder,the cylinder head being provided with a pressure chamber incommunication with said control member, conduit means communicating saidchamber with the lubricating system of the compressor and whereby alubricating fluid under pressure may be admitted to said chamber to movesaid control mem-ber clearof the suction valve and permit the latter tofunction normally to load the cylindenand means operable in accordancewith load requirements of the refrigeration system for controlling thepressure of fluid in said chamber.

3. In a refrigeration system, a compressor having a cylinderwith areciprocating piston there in and a crankcase provided with a force feedlubrication system, said cylinder being provided with a head formed withsuction and discharge ports and having suction and discharge valvescontrolling said ports, valve springs tending to normally urge saidvalves to seated position, a;

spring pressed reciprocating control member hav- 4. In a refrigerationsystem having a closed reirigerant circuit, a compressor having acylinder by fluidpressure may be applied thereto to release the suctionvalve and permit the latter to move to seated position, said conduitmeans including arestricted conduit connected into the lubricationsystem and a conduit of greater flow capacity connected to the restricedconduit and leading to the control means, and valve means controllablein accordance with load requirements of the refrigeration system forregulating the passage of fluid fromsaid restricted conduit to itsenlarged connecting conduit.

5. In a refrigeration system, a compressor having a cylinder with areciprocating piston therein and a crankcase provided with a force feedlubrication system, said cylinder being provided with suction anddischarge ports and spring pressed valves controlling said ports, aspring pressed control member adapted to engage the suction valve andovercome its coacting spring and move the suction valve clear. of itsseat to unloading position, the compressor being provided with apressure chamber within the region of said control member, conduit meansconnected into the lubricating system for conducting fluid underpressure to said pressure chamber, said conduit means including aconduit of restricted flow capacity tapped into the system and conduitscon-i necting with said restricted conduit one of which leads to saidpressure chamber and is of greater flow capacity than the restrictedconduit and the other of which constitutes a return conduit and leadsback to the lubricating system, and a conrol valve in said latterconduit operable to control the ilow of oil therethrough to thereby alsocontrol the pressure built up in the pressure chamber.

6. In a refrigeration system, a compressor having a cylinder with apiston therein, a head for said cylinder having suction and dischargeports, spring pressed suction and discharge valves for said ports,a-main suction space and a main discharge space communicating with saidsuction and discharge ports, a cylindrical member mounted in said headand separating said main suction and discharge ports, a reciprocatingcontrol member adjacent said cylindrical member and adapted to engagethe suction valve and move it from its seat to unloading position,spring means tending to normally urge the said control member intoengagement with said suction valve .to hold the latter in unloadingposition, said head being provided with a fluid pressure chamber withinthe region of said control member, and means for applying controlledpressure to said chamber to displace the control member from saidsuction valve and permit the latter to function normally as a suctionvalve I. In a refrigeration system, a cylinder with a piston therein, ahead for said cylinder, said head being provided with suction anddischarge ports, spring pressed suction and discharge valve for saidports, a reciprocating control member mounted in said head and adaptedto engage said suction valve, spring means-for normally urging saidcontrol member against the suction valve to with a reciprocating pistontherein and a crankcase provided with a force feed lubrication sysmovethe latter to unloading position, fluid pressure meansfor retractingsaid reciprocating member against the tension of said'sprlng means torelieve pressure from the suction valve and permit the latter to'function normally as a suction valve, and means resiliently mounting thecylinder head.

8. In a refrigeration system, a compressor hav ing a cylinder with areciprocating piston therein, a cylinder head for said cylinder and avalve case overlying said cylinder head, said head and valve case beingprovided with suction and discharge ports, spring pressed suction anddischarge valves for said ports, a spring pressed control member mountedfor vertical reciprocation in said head and having a part adaptedto'engage the suction valve, spring means normally urging said controlmember downwardly to hold the suction valve clear of its seat inunloading position, said head being provided with a fluid pressurechamber within theiregion of said plunger,

means for admitting fluid under pressure to said chamber to counteractsaid spring means and permit the suction valve toseat, andjmeansresiliently mounting said head and valve. case together with saidcontrol member permitting the entire assembly to become displaced asaunit in the event an incompressible body becomes interposed between thepiston and 'said head.

9. In a refrigeration system, a compressor having a cylinder with areciprocating piston therein, a cylinder head for said cylinder and avalve case overlying said cylinder head, said head and valve case beingprovided with suction and discharge ports, spring-pressed suction anddischarge valves for said ports, a reciprocating capacity controlmembenhaving a part adapted to engage the suction valve, spring meansnormally 'urging said capacity control. member to a position where itdisplaces; the suction valve from its seat to unloading position, meansto overcome the unloader spring means so that the compressor can operatenormally and means resiliently mounting the cylinder head, valve cageand capacity control memberv for movement as a unit in' the cylinderwall in the event an incompressible body becomes interposed between thepiston and cylinder head.

10. In a refrigeration system, a compressor having a cylinder with areciprocating piston therein, the wall of the cylinder beingcounterbored at the upper extremity of the cylinder, a head mounted insaid counterbore and provided with suction and discharge ports andsuction and discharge valves overlying said ports, a capacity controlmember also mounted for reciprocation in said counterbore and havingapart adapted to abut said suction valve, spring means normally urgingsaid capacity control member intoposition where it moves the suctionvalve clear of its seat tolunload the cylinder, means to overcome theunloader spring means so that the compressor can operate normally andmeans resiliently mounting the cylinder head, capacity. control memberand valve assembly for movement as a unit in the event anincompressiblebody'be crankcase provided with a force feed lubricating comesinterposed between the piston and cylinder head.

11. In a refigeration system having a closed refrigerant circuit, acompressor having a cylinder with a reciprocating piston therein and asystem and a pressure chamber, said lubricating system including a pumpmounted within the crankcase and discharging oil under-pressure into 1ciprocating' piston therein, a resiliently mounted safetyhead for thecompresser, suction and discharge valves in said head, anda capacity.control member co-active with said suction valve to displace the latterfrom its seat to unload the cylinder and means to restore the compressorto normal operation.

13. In a refrigeration system, a compressor having a cylinder with areciprocating piston therein, a head for said cylinder having suctionand discharge ports, spring-pressed suction and discharge valves forsaid ports, a cylindrical member mounted on said head and separating theformed with a fluid pressure chamber, and means for communicating fluidpressure to said chamber to raise the control sleeve clear of thesuction valve and permit the latter to function normally as a suctionvalve. I

14. In a refrigeration system having a closed refrigerant circuit, acompressor having a cylinder with a reciprocating piston therein and acrank case provided with a force-feed lubricating system,-said cylinderbeing provided with suction and discharge ports and spring pressedsuction and discharge valves for controlling said ports, control meansadapted to engage the suction valve and move it from its seat againstthe pressure of its valve spring to unload the cylinder,

- a pressure chamber in communication with said control means, meansdefining a series of interarea thereabove into a main suctlonspace and amain discharge space, a reciprocating control member in the form of acylindrical sleeve surrounding said cylindrical member and arranged atits lower end to engage the suction valve, a

spring operatively connected to said control sleeve and normallyexerting a downward thrust thereon with suflicient force to urge saidsleeve into engagement with the suction valve and hold the latter inunloading position, said head being connected flow passagescommunicating the lubricating system with said pressure chamber andwhereby fluid pressure may be applied to the control means to effectrelease of the suction valve and permit the latter to move to seatedposition, said flow passages including a conduit of restricted flowcapacity connected into the lubricating system and arranged to dischargeinto a conduit of greater fiow capacity leading to the pressure chamberand to also discharge into a return conduit leading back to thelubrication system, and valve means controllable in accordance with theload,requirements for regulating the flow of fluid through said returnconduit. I

' LEON BUEHIER, JR.

